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In this blog post we'll explore the basic steps to deploy a Qt application for macOS, including assigning an icon for the application and adding assets. It is assumed that you have Qt Creator and Qt version 5.7.1 or later installed and configured on your macOS computer. If not, this blog can be used as a reference point.
Getting Started
The first thing to understand is the structure of a macOS application. MacOS makes use of the concept of bundling. Mac applications are technically folders with .app extensions.
From a normal user's standpoint from the GUI, it is a single...

In this final installment of our Qt Developer's Bag of Tricks series, I'll look at some helpful tools that didn't fit into any of the categories covered previously.
GammaRay
GammaRay (1) is a tool for examining and manipulating the internals of Qt applications at run time. Unlike conventional debuggers, it understands the implementation of Qt, allowing it to visualize application behavior at a higher level, including signals, slots, properties and even scene graphs, model/view and state machines. It is free software, licensed under the GPL. A screen shot is shown below,...

Computer software sometimes has a requirement for generating random numbers. Applications include games, simulations, cryptocurrency, and security software. Generating true random numbers is surprisingly difficult, and many applications use a series of pseudorandom numbers, sometimes seeded with an initial value that is not constant, such as user input or the current time or date.
The ISO standards for the C and C++ programming languages and other standards, such as POSIX, define standard random library functions. The most well-known are probably the rand() and srand() functions.
Since...

While you can develop software using just a text editor and the command line (and many people do), you'll often see productivity gains by using a graphical integrated development environment (IDE). Here are a few options for IDEs that are suitable for Qt development.
Qt Creator
The "official" Qt IDE, Qt Creator (1) is open source, cross-platform, and written using Qt. It is usually the IDE of choice for Qt development unless you have some special requirements or a personal preference. Its support for mobile and embedded platforms really pays off in making it easy to build, deploy,...

Various tools that can be lumped together under the category of simulators and emulators can be useful during development, especially for embedded systems. A number of products use virtualization to run one operating system on top of another one. This allows you to run Linux on top of Windows, for example, or vice versa.
This is often useful for embedded development where you might want to develop on a Windows desktop, but need to run a cross-compiler or SDK that is only supported under desktop Linux.
Virtualization allows you to run Linux in a virtual machine under Windows, and still...

As 2017 draws to a close, I'd like to take a look back at some of the significant events of the past year that are relevant to the Qt framework and the ecosystem around it.
Qt Releases
The Qt Project continued to follow the process of generating two minor releases per year. Qt 5.9.0 was released on May 31, with subsequent patch releases for 5.9.1, 5.9.2, and 5.9.3 during the course of the year.
Note that the 5.9 series is a Long Term Support (LTS) release, with a promise of support for three years. The previous LTS series was 5.6, which is still being supported. The current...

In the past, embedded systems often ran very small operating systems with no filesystem, or even ran on the "bare metal." With the increasing power and lower cost of hardware, including SOCs (Systems on a Chip), many embedded systems are moving to a full operating system, often based on Linux.
One advantage of running Linux on an embedded device is that many of the tools and utilities you are familiar with on a desktop Linux system are available in this environment, as well. While the final product may not ship with them, as a developer you can have access to a shell, basic commands,...

Memory and resource leaks are the stuff of nightmares for programmers. If a program doesn't properly free memory or other resources, it may appear to run correctly, but randomly crash or misbehave after working normally for hours or days. All too often, the problem is only discovered just before the application is supposed to be shipped to customers.
While Qt helps somewhat with it's object model, resource leaks can occur with any programming language like C++ where the user is responsible for managing memory or other resources like file handles. Let's take a look at some of the tools that...

Static Analysis (1), or more correctly, Static Program Analysis, is a method of analysis of computer software that is performed by examining source code without actually executing it. It is typically performed by automated tools.
Static analysis is increasingly used in the development of safety-critical software, such as medical, nuclear and aviation systems. In this installment of our series on software development tools, today we look at some options for static analysis, focusing on those that support C++.
CppCheck
Cppcheck (2) is a static code analysis tool for the...

An interesting feature coming in Qt 5.10 is a new Qt back end that uses WebGL for rendering. It allows Qt applications (with some limitations) to run in a web browser that supports WebGL.
What Is it?
The new back end uses WebGL, which stands for Web Graphics Library. WebGL is a JavaScript API for rendering 2D and 3D graphics within any compatible web browser without the use of plug-ins. The API is similar to OpenGL ES 2.0 and can be used in HTML5 canvas elements.
The new back end will be introduced as a technical preview feature in Qt 5.10.0 and is included in the Alpha and...

We’re back from another successful Qt World Summit in Berlin, which boasted the largest crowd (1000+) to date. The popularity of the conference is a strong indicator that the Qt community continues to grow as does the number of commercially available products built with Qt. Our booth alone showcased a touchscreen sonar and navigation device for the marine industry, a home mechanical ventilator for respiratory support, a fully integrated, intelligent infusion pump, and a modern and elegant IVI system.
Thanks to everyone who stopped by our booth — and congratulations to our iPhone X...

Continuing our Qt Developer's Bag of Tricks series, this time I'll give you an overview of some applications that come under the general category of tracing. (I'll also include some test coverage tools here too since they don't fit in any other categories in this blog series.)
Tracing is often an effective and efficient debugging technique that doesn't require as much effort as using a debugger. It can be particularly useful for programs that you didn't write and don't have source code for. If a program crashes or hangs, tracing it may quickly identify the cause of the problem....

Developers often have a desire to speed up their code to make it run more quickly. Some well-known advice on this topic, attributed to the programmer Michael A. Jackson, says:
Rules of Optimization:
Rule 1: Don't do it.
Rule 2: (for experts only) - Don't do it yet.
Sometimes a third rule is added:
Rule 3: Profile before optimizing.
The key point here is not to optimize your code until you have a correct, clearly written, and unoptimized solution. Then, use tools to identify where the bottlenecks are and focus on them. Software performance often follows a so-called 80/20 rule where...

Experienced software developers tend to build up a set of tools that they find indispensable for development, testing and debugging. But if you ask a group of developers what their "go to" tools are for various tasks, it is surprising how different the answers can be. I've also found that many developers are unaware of some very useful tools that can save hours of effort.
In the Qt Developer's Bag of Tricks series, which kicks off with today's post on debuggers, I'll cover several tools that the development team here at ICS has found useful.
Scope
Software...

Continuing our QML Controls from Scratch series, this time we will implement a vertical ScrollBar, which is the vertical line segment you often see on the right of a touch user interface as you scroll vertically through a list of items. ScrollBar is quite a bit different than the other controls in this series as it can't be run stand-alone in qmlscene. Rather, it is designed to be a direct child of a ListView or GridView (the ScrollBar's parent). The ScrollBar's position (y) and height are computed with a bit of math, based proportions of Flickable's contentHeight and contentY, as...

When launching a new project using Qt, you have to decide whether to buy a commercial license or use the free, open source version. It’s an easy decision. Free is better, right?
Well, not always. Here's why.
In a typical year, ICS works on more than 75 new and unique embedded devices based on Qt. Everything from a flying autonomous taxi service to lifesaving medical devices to an industrial control system for a shrink-wrap pallet machine. But despite the differences in these devices, every ICS proposal for our software development services includes the statement: ICS recommends...

In this post we'll take a look at one of the newer Qt modules: Qt Speech.
What Is Qt Speech?
Qt Speech is a module providing cross-platform support for text to speech. It supports text to real-time speech output. Common use cases for text to speech include enabling software for visually impaired users and scenarios where users cannot utilize a touchscreen, mouse, or keyboard input, such as in-vehicle applications. The module may support other features, such as speech recognition, in the future.
The Qt Speech module was first introduced in the Qt 5.8.0 release. As of Qt 5.9.0 it...

Continuing our QML Controls from Scratch series, this time we will implement a Slider. The Slider has value, minimum, and maximum public properties. Slider is implemented with a single MouseArea that covers the entire control and utilizes onPositionChanged to handle the user sliding the "pill" (the portion which the user moves ) left and right.
The background "tray" (a horizontal line, which can be tapped) is split into left and right pieces so that it doesn't show through the pill when enabled is set to false (since the pill is partially transparent in the disabled state)....

In previous blog posts I've covered how to configure Qt Creator for development on Linux (1), Windows (2) and MacOS (3) desktop systems and for embedded development on the Raspberry Pi (4).
We're often asked in our training classes and consulting projects how to set up the Qt Creator IDE for embedded development using the Yocto (5) framework.
In this post I'll discuss how to do this, including instructions covering how to build a Yocto toolchain with Qt if you don't already have one from your hardware vendor.
Prerequisites
Development for Yocto is normally done on a Linux desktop...

Continuing our QML Controls from Scratch series, this time we will implement a Switch. Switch is similar to CheckBox with the exception that it has a slidable pill (implemented with a second MouseArea and drag property) and no text property. A Switch can be toggled either by tapping or dragging.
Switch.qml
import QtQuick 2.0
Rectangle { // size controlled by height
id: root
// public
property bool checked: false; // oncheckedChanged: print('oncheckedChanged', checked)
// private
width: 250; height: 50 // default size
border.width: 0.05 *...

The Windows Subsystem for Linux (WSL) is a new feature of Windows 10 (1) that allows you to run native Linux programs directly on Windows, alongside other Windows applications.
When WSL is enabled, it installs an Ubuntu user-mode image that was created by Canonical, the company behind Ubuntu Linux. It loads and runs the Linux Bash shell and provides many of the command-line tools that you would expect when running Ubuntu Linux. It is based on the Ubuntu 14.04.5 LTS release.
Installation
It is easy to install. (2, 3, 4) Turn on developer mode and then enable the Windows Subsystem for...

Continuing our QML Controls from Scratch series, this time we'll implement a CheckBox. We'll also get RadioButton almost for free. CheckBox is similar to Button with the exception that it holds checked/unchecked state in the checked property. All QML properties have an associated *Changed signal, so the checkedChanged() signal (useful for C++) causes onCheckedChanged to run when the property checked changes.
CheckBox also serves as a radio button if a client sets radio: true, which is all RadioButton.qml does. To get multiple radio buttons to act together in a group, put a RadioButton...

Two earlier blog posts (1) (2) covered how to set up Qt and Qt Creator on Windows and Linux systems. Let's look at installation on the remaining major desktop platform, macOS.
Thanks to the unified Qt installer, the process is very similar to that on Windows and Linux, so we'll just cover some of the differences and highlights of the Mac install.
Assumptions and Prerequisites
For this example we'll install Qt 5.7.1, which is supported on macOS version 10.8 and later.
The C++ compiler used by Qt on macOS is the Clang compiler, provided as part of the Xcode development tool....

QML provides a very powerful and flexible framework for developing user interfaces. The basic elements that are provided are low level, so you typically need to build up the components of your user interface into widget-like controls. Developing a set of common QML controls can greatly reduce the overall development effort of your project.
In this series (which assumes you're familiar with basic QML), we will create a set of minimalistic QML controls from scratch (i.e. from QML primitives Item, Rectangle, Text, etc.) that can be used as a starting point for...

In an earlier blog post (1) I described how to create a widget with a Qt Designer plugin interface so it can be viewed within Qt Designer. With the increased interest in using Qt from the Python programming language, I asked one of our developers to reproduce the same example, but implement the widget in Python with PyQt.
Not all the steps to do this are obvious so I'll walk you through.
Example Files
The download link (2) contains the example code referenced in this blog post. It includes the following source files:
ledwidget.py: A port of...

Happy New Year!
In previous blogs I have covered installing Qt and Qt Creator on Windows and on Linux using the Qt installer and pre-built binaries. In this post, aimed at developers with novice-level Qt skills, we'll look at how you can build Qt yourself from source code.
Rationale
Why would you want to build Qt from source? While the downloadable pre-compiled binaries are convenient and save time, you may want to build Qt using a different configuration from that provided by The Qt Company. You may, for example, want to enable or disable different options...

As 2016 draws to a close, I'd like to take a look back at some of the significant events of the past year that are relevant to the Qt framework and the ecosystem around it.
Qt Releases
Starting in 2016, Qt 4 was officially at end-of-life status and no longer supported. The last release was Qt 4.8.7 in May 2015 and no new releases are planned.
This past year introduced the first long-term support (LTS) release of Qt, following the model of some other open source projects like Ubuntu to make a commitment to support a release for five years. Currently, this is the 5.6 series with the...

In this two-part series, we'll look at an interesting Internet of Things (IoT) application that uses an Arduino controller and two XBee wireless modules in conjunction with a Qt-based application.
Part 1 provides an overview, demonstrates communication between two applications using the XBee, and describes the hardware setup. Part 2 covers the configuration and programming of both the desktop application and the Arduino code.
Introduction
There are many different XBee models available with various wireless protocols, line of sight ranges, data transmission rates, RF...